Abstract: A system for air compression, storage and expansion may include a low-pressure and a high-pressure compressor, a motor, a heat storage, an air storage volume, a high-pressure and a low-pressure turbine, and a generator. The system may further include a first air path connecting sequentially the low-pressure compressor, the heat storage, the high-pressure compressor, and the air storage volume. The system may further include a second air path connecting sequentially the air storage volume, the high-pressure turbine, the heat storage, and the low-pressure turbine.